Module window 

Windowing operations for stream processing.

This module provides abstractions for grouping stream elements into bounded windows for aggregation and processing.

Overview

Windowing is fundamental to stream processing, allowing bounded computations over unbounded streams. Windows group elements based on:

• Time: Group by event time or processing time
• Count: Group by number of elements
• Session: Group by activity with gaps

Core Concepts

• TimeWindow: Represents a window boundary (start/end time)
• WindowAssigner: Assigns elements to windows
• WindowTrigger: Determines when to emit window results
• LateDataPolicy: Handles elements arriving after window closes

Window Types

• TumblingWindowAssigner: Fixed-size, non-overlapping windows
• SlidingWindowAssigner: Fixed-size, overlapping windows
• SessionWindow: Gap-based dynamic windows

Example

use streamweave::window::{TimeWindow, TumblingWindowAssigner, WindowConfig};
use std::time::Duration;

// Create a tumbling window of 5 seconds
let assigner = TumblingWindowAssigner::new(Duration::from_secs(5));

Structs

BoundedOutOfOrdernessGenerator

Generates watermarks allowing for bounded out-of-orderness.

CountTrigger

Trigger that fires after a specified count of elements.

CountWindow

A count-based window that holds a fixed number of elements.

CountWindowAssigner

Count-based tumbling window assigner.

EventTimeTrigger

Default trigger that fires when the watermark passes the window end.

GlobalWindow

Global window that contains all elements.

GlobalWindowAssigner

Global window assigner that assigns all elements to a single window.

LateDataHandler

Handles late data according to the configured policy.

LateDataStats

Statistics about late data processing.

MonotonicWatermarkGenerator

Generates watermarks that follow the maximum observed timestamp exactly.

NeverTrigger

Trigger that never fires (for global windows).

PeriodicWatermarkGenerator

Generates watermarks at fixed intervals regardless of event arrival.

ProcessingTimeTrigger

Processing time trigger that fires at regular intervals.

SessionTrigger

Trigger that fires when the session gap timeout expires.

SessionWindow

A session window with dynamic boundaries based on activity gaps.

SessionWindowAssigner

Session window assigner that creates gap-based windows.

SlidingWindowAssigner

Sliding window assigner that creates overlapping windows.

TimeWindow

A time-based window with start and end timestamps.

TumblingWindowAssigner

Tumbling window assigner that creates non-overlapping windows.

Watermark

Represents a watermark in event-time processing.

WindowConfig

Configuration for window operations.

WindowState

Tracks the state of a window including its watermark context.

Enums

LateDataPolicy

Policy for handling late data (elements arriving after window closes).

LateDataResult

Result of evaluating whether an element is late.

TriggerResult

Result of trigger evaluation.

WindowError

Error type for window operations.

Traits

WatermarkGenerator

Trait for generating watermarks from observed event timestamps.

Window

Trait for window types that can be used with WindowState.

WindowAssigner

Trait for window assigners that assign elements to windows.

WindowTrigger

Trait for window triggers that determine when to emit results.

Type Aliases

SharedWindowAssigner

Shared window assigner reference.

WindowResult

Result type for window operations.